Unit 3 - Gases Intro and Boyle's Law

Particle Theory

1. All matter is made of particles.

2. These particles are constantly in motion.

3. Higher-energy particles move faster than lower-energy particles.

4. The particles in solids are closer together than in liquids; the particles in liquids are closer together than in gases.

Properties of Gases

1. Have no shape or volume on their own, but they completely fill a container

2. Are highly compressible (aerosol cans)

3. Increase in volume, pressure, or both when heated

4. Decrease in volume when under pressure

5. Diffuse rapidly and mix with other gases

6. Halogens, oxygen, and hydrogen are reactive

7. Noble gases are non-reactive

Diffusion

the act of spontaneous spreading out of particles. Lighter gases (lower molar mass) move more quickly than heavier gases. Diffusion can occur in any liquid.

Temperature

affects the pressure and volume of a gas. Increasing the temperature of a gas causes the volume to increase. An increase in volume means an increase in pressure (if the vessel can not expand).

Pressure

the force per unit of area

Gas pressure

Gas particles are constantly moving and bumping into one another. The collision of these particles with objects in their path (a container, a person, etc.) is what leads to pressure.

atmospheric pressure

pressure exerted by atmosphere / air

Boyle’s law

Pressure is inversely proportional to the volume of a gas when temperature is constant. Volume of a gas is increased = the pressure the gas exerts decreases. Volume of a gas is decreased = the pressure increases.

stp

Standard Temperature (0 degrees Celsius) and Pressure (101 kPa)

satp

Standard Ambient Temperature (25 degrees Celsius) and Pressure (100kPa).